Process of electroplating non-m etallic articles



(No Model.)

W. H. WINSLOW. V PROCESS OF ELEGTROPLATING NON-MBTALLIG'ARTIGLES. No.423,101.

Patented Mar. 11, 1890.

UNITED STATES ATENT Grrrcn.

VILLIAM ll. WINSLOWV, OF CHICAGO, ILLINOIS.

PROCESS OF ELECTROPLATING NON-METALLIC ARTICLES.

SPECIFICATION forming part of Letters Patent No. 423,101, dated March11, 1890.

Application filed October 28, 1889. Serial No. 328,375- (No model.)

T0 at whom it may concern:

Be it known that I, WVILLIAM I-I. IVINSLOW, of Chicago, in the county ofCook and State of Illinois, have invented certain new and usefulImprovements in the Process of Electroplating Non-Metallic Articles; andI do hereby declare that the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings,and to the letters of reference marked thereon, which form a part ofthis specification.

This invention relates to a process of constructing articles of thatkind, consisting of a base or form of wood or other non-metallicsubstance, and a coating or layer of metal applied thereto byelectro-deposition.

My process consists in its main or essential feature in applying to orover the surface of the article to be coated with metal metallic strandsor fine wires, which are connected with the electric conductors throughwhich the current passes and which serve to produce apracticallysimultaneous and uniform deposit of metal on the surface ofthe article.

My process includes a certain method of treating a non-metallic base orform when the same is made of wood, to prevent the same being acted uponby the liquid of "the bath and swelled or expanded thereby, to theinjury of the finished article.

In carrying out my process when a wooden form or base is employed, suchform is first treated with paraftine until thoroughly permeated orsaturated with the same. The form is then inserted in a bath ofelectroplating-liquid composed of the same ingredients and having thesame density as the bath into which it is immersed during theelectroplating operation. The form is then varnished with a suitablewaterproofing mixture-such as copal varnish or gutta-percha dissolved innaphtha. The surface of the form then overlaid with a metallic strand orsmall wires arranged openly and connected with the electric conductorwhich is attached to the article. Commonly the wire will be applied bywrapping or winding it about the form and without any great precision,as it will suffice if the coils of wire are disposed with some degree ofuniformity over the entire surface of the form. The surface of the formis then coated with graphite or other parts than others.

suitable conducting material, as common in electroplating articles whichare themselves non-conductors, and the form is then in read 1- ness tobe suspended in the electroplatingbath and metal deposited thereonin theusual manner until a coating or layer of' desired thickness is obtained.

The object of the metallic strandor wire is to insure the evendistribution of the metal over the form as the metal is depositedthereon, it being well known that in electroplating the metal isdeposited more promptly and rapidly on the part of the article nearestthe pointat which the electric conductor is attached to the same, sothat in the case of an article which is made of non-conductingmaterialsuch,for instance, as awooden formthe deposition begins to takeplace on the portion of the article nearest the conductor and graduallyspreads until the entire surface is covered. By reason of this fact inthe case of a large article not only does it take a long time tocompletely cover the article; but the coating applied is much thicker insome By overlaying the surface with fine wires, as above described,however, deposition begins along each Wire and spreading out from thesame soon covers the entire surface, thereby not only greatly shorteningthe process of plating but enabling, the coating to be applied with amuch greater degree of uniformity than heretofore.

Upon the removal of the electroplated form from the bath it will befound that the metal deposited over the wires forms a series of ridgeson the surface of the metal coating; but these ridges are removed bygrinding or otherwise in the same manner that other inequalities areremoved in smoothing and polishing the coating as common heretofore.

In the accompanying drawings I have shown an article as it appearsduring the several steps or operations of my process.

In said drawings, Figure 1 is a side view, partly in section, of awooden form or base for forming a baluster. Fig. 2 is a side view of thesame after being treated in accordance with my process and preparatoryto being placed in the electroplat-ing-bath. Fig. Sis a longitudinalsectional view, on an enlarged scale, of a portion of a balustcr afterhaving the metal layer or coating applied thereto.

Fig. 4 is a similar view, partly in side elevation, of the finishedarticle.

As illustrated in Fig. 1, A indicates the form, which is turned in themanner illustrated or otherwise brought to the desired shape, such formbeing preferably made of hard wood and given a smooth finish. The formillustrated is that of a turn ed spindle or baluster.

G O are metal screw-eyes, which are conveniently inserted in oppositeends of the wooden form, for the purpose of connecting with the same awire or' metal conductor by which the form is suspended in the bath ofthe electroplating apparatus, and by means ofwhich the electric currentis conveyed to the form.

I have found that the best results are produced by employingperfectly-dry wood for making the form, in order that the wood may bethoroughly saturated or permeated with the paraffine, and for thispurpose I not only employ kiln-dried lumber, but I subject the form,after it has been shaped and fi nished, to a temperature sufficientlyhigh to dry off all moisture, and I insert the form in a bath of meltedparaffine when said form is taken from the heating apparatus, so thatthe latter'is in condition most favorable for the entrance to its poresof the melted paraffine.

I have found in practice that by suitably heating and drying the woodenform the metal paraffine permeates the same throughout. After the form Ahas been saturated with the paraffine 1n the manner described, andremoved from the paraffine bath, it is allowed to cooland is then placedin a bath of the same character as that which is afterward employed inelectroplating the same form-as, for instance, if the coating is to beof copper anda bath consisting of a saturated solution of sulphate ofcopper is employed in plating, the form will be immersed in a bath ofthe saturated solution of sulphate of copper. The form is allowed toremain in such bath a short time only, the object of this treatmentbeing merely to saturate with sulphate of copper the exterior pores orinterstices of the wood which are not completely filled by theparafline. When a saturated solution of the plating material is used, aswill ordinarily be the case, the surface of the form will contain a veryslight coating of the crystallized ma terial.

The treatment of the wooden form by soaking in the electroplating-bathappears to have. the effect of filling the pores of the wood which wouldotherwise be filled by the e11- trance of the liquid of the bath in caseof a break or rupture of the waterproof coating of the form at the timeit is placed in the bath for. plating, so that in case there is such abreak or rupture in the waterproof coating employedthe contact of thebath-liquid with the wooden form has no effect upon the latter. The formis not usually allowed to become thoroughly dried before the applicationof the water-proof coating,'but the latter is immediately appliedthereto, so that while the water will quickly evaporate from the surfaceof the form, thereby leaving the same covered with a slight coating ofthe crystallized plating solution, (over which varnish or otherwater-proof coating may be applied without difficulty,) the intersticesor pores of the wood remain filled with the solution, either in acrystallized or liquid state, or both, thereby preventing the solutionfrom afterward penetrating such interstices or pores, with the result ofexpanding the form. In other words, the wood is expanded or swelled bybeing immersed in the solution, and not being dried before thewater-proof coating is applied, no further expansion can take placeduring the plating operation. 7

I have found that when the form is treated with paraffine and thenvarnished with copal or given a surface of other water-proof substancebefore immersion in the bath the liq.- uid of the bath is liable to findaccess to the surface of the wood and to expand or swell the same duringthe process of plating, so that the metal coating becomes cracked orsplit before it is thick or strong enough to withstand the expansion ofthe wood, and in practical work I have found that a large percentage ofarticles thus treated with paraffine and varnish alone are injured bythe splitting of the metal coatingin this manner. By soaking the woodenform after it is saturated with paraffine, but before varnishing, in thesame solution as that composing the electroplating-bath, however, theseresults are enti rely avoided and perfect results are in every instanceobtained.

After treatment of the articles by immersion in the bath-liquid, asdescribed, the form is then covered or coated with copal varnish orother water-proof substance. For small articles-such as ornamentalspindles, slender balusters, and other small objectsthe employment ofcopal varnish is sufficient; but in many of these articles it may befound desirable to coat those parts of the article at which'the end ofthe grain of the wood is exposed with a solution of gutta-percha andnaphtha or other heavy and impervious waterproofing substance, it beingentirely obvious that the parts of the form at which the end of thegrain of the wood is exposed are most likely to be entered by the liquidof the bath. In the case of larger articles it may be found desirable tocoat the entire surface of the same with gutta-percha dissolved'innaptha or other substance, giving a more solid and heavier coating thanthat afforded by copal varnish alone. After treatment with water-proofcoating, as described, the form is then overlaid with fine wire,prefer-' ably by wrapping or coiling a wire spirally about the same, asindicated by B B. Gommonly for this'purpose the article will be placedin a lathe and revolved and the wire wrapped around the same as it isrotated' When the form is provided at its ends with tire length of thewire B. In whatever mannor the wire is disposed, however, it must beconnected with the metal wires or conductors erably is so, in order thatit may be easily applied to the surface of the form and will projectslightly above the same. I have found it desirable to wrap the wireabout the 3 form before the varnish or other water-proof coating thereonhas dried or become hard, so that the wire will adhere to or slightlysink into the surface of the varnish or coating, and will thereby beheld in place and prevented from slipping off of the rounded orprojecting parts of the form, it being obvious that it will i besomewhat difficult to wrap the wire closely and tightly about an articleof irregular shape without the wire slipping on the rounded, conical, orprojecting parts of the form, and thereby becoming loose and getting outof place. By employing fine and flexible Wire and applying the samewhile the coating or varnish is soft the disposal of the wire over thesurface of the form can be easily and quickly accomplished by unskilledworkmen. After the form has been wrapped with wire the same is coveredwith a coating of graphite or other conducting material, as

common heretofor in electroplating non-metallic substances. It is foundthat in electroplating large objects, when covered with a thin coatingof graphite, as common heretofore, the deposition of the metal takesplace very slowly, beginning at the points where the electric conductorsare attached to the article and gradually spreading over the same untilthose parts of the surface most remote from the conductors are covered.In electroplating a large object, therefore-such as a newel-post for astairway-a long time is required to procure a sufficient thickness ofmetal,while the parts of the article nearest the conductors receive acoating much thicker than is needed. When the surface of the article isoverlaid with line wire connected with the conductors, however, thedeposition of the metal begins simultaneously throughout the .entirelength of the small wire, and spreading laterally therefrom soon meetsin the space between the wires, and thus covers the entire surface ofthe form in a short time. The deposition of metal is thus caused to takeplace with practical uniformity over the entire surface of the form, sothat the time required for plating is much reduced,

while the resulting coating is practically uniform in thickness.

Fig. 3 shows the Wooden form after the coating D has been appliedthereto and illustrates. the manner in which the metal is deposited overthe fine wires, thereby forming j narrow ridges on the exterior surfaceof the coating. These ridges are, however, removed in the subsequentsmoothing or polishing of the article in the manner clearly shown inFig. 4. WVhen the coating is of considerable thickness and the wire isvery fine, the said wires will be embedded in the metal coating or shellD, as illustrated in Fig. 4. It is, however, not necessary that themetal coating should be thicker than the wires, and in some instancesthe coating will be removed in smoothing or polishing, so as to cut intoor expose the wires. This will make no difference in the general result,however, inasmuch as the wires may be made of the same metal as theelectro-deposit coating, in which case they will not be visible, or ifthey are of a slightlydifferent color the oxidization or other treatmentof the surface of the metal coating commonly employed in finishingornamental articles will prevent the wires from being seen.

Commonly in carrying'out the process above described the wooden formwill first be covered with a relatively-thick coating of cop: per, andafter this coating has been smoothed and polished a final coating ofnickel, silver, bronze, or other metal will be applied to give asuitable exterior finish to the same.

As a separate improvement without restriction to the other steps, myinvention consists in the process of electroplating articles composed ofnon-metallic material, which embraces the step of overlaying sucharticle with wire connected with the electric conductors in the mannerdescribed for the purpose of facilitating the deposition of the metalthereon, it being entirely obvious that the use of wire or wires in themanner described is appli cable to substances other than wood, and thatas far as the use of wire is concerned wooden articles may be renderedwater-proof otherwise than in the particular manner herein described,and that articles other than wood may not require any treatment to makethem water-proof, or if they do require such treatment they may berendered water-proof otherwise than in the particularmanner hereindescribed.

The invention comprises as another separate improvement the processherein set forth, by which a wooden form may be protected from theaction of the electroplating-bath on the wood, it being obvious thatthis step can be used without restriction to the use of paraffine forsat urating the wood, the wire, or the coating of water-pro of material,for the rea son that .such treatment of the wood may sometimes beemployed on articles so small that their use will not be necessary or ofIIO practical loenefit. But it is to be understood that the foregoingsteps can be used separately as well as collectively in connection withthe process of protecting the wood from the action of theelectroplating-hath. For instance, the saturation of the wood withparaffine only, or the coating of the same with a water-proof materialonly, or both, may be used with the step of treating with the bathliquidto protect the wood against the action of the bath in electroplating,according to the size or shape of the article, the character of thewood, and other circumstances.

.I claim as my invention 1. The process of coating non-metallic articleswith metal, which includes the overlaying of the surface of the samewith metallic strands or wires connected in the electric circuit, of theelectroplating apparatus and afterward electroplating the article.

2. The process of coating articles of wood.

with metal, which includes the steps of applying to the surface of thesame a liquid similar to that used in the electroplating-hath,

coating the same with an electric conducting ing to the surface of thesame a liquid similar to that used in the electroplating-bath, coatingthe same with water-proof material,

coating the same with an electric conducting material, and'finallyelectroplating the article.

5. The process of coatingarticles of wood with metal, which includes thesteps of saturating the wooden article with paralfine, applying to thesurface of the same a liquid similar to that used in theelectroplating-bath, coating the same with water-proof material, coatingthe same with an electric conducting material, and finallyelectroplating the article.

6. The process of coating articles of wood with metal, which includesthe steps of saturating the wooden article with paraffine, applying tothe surface of the same a liquid similar to that used in theelectroplating-bath, coating the same with water-proof material andoverlaying the surface of the same with metallic strands or wires, andfinally electroplating the same.

7. The process of coating articles of wood with metal, which includesthe steps of heating the wooden articles, immersing the same whileheated in hot melted paraffine, applying to the surface of. the same aliquid similar to that used in the electroplating-bath,

coating the same with water-proof material, overlaying the surface ofthe same with metallic strands or wires, applying a coating of graphiteor other conducting material, and finally electroplating the article.

In testimony that I claim the foregoing as my invention I affix mysignature in presence of two witnesses.

WILLIAM H. WINSLOW.

WVitnesses:

O. CLARENCE PooLE, HARRY COBB KENNEDY,

